CN110773231B

CN110773231B - Preparation method of nano-scale fuel oil catalytic oxidation-adsorption desulfurization catalyst

Info

Publication number: CN110773231B
Application number: CN201911185323.1A
Authority: CN
Inventors: 杨万亮; 陈美丽
Original assignee: Guizhou University
Current assignee: Guizhou University
Priority date: 2019-11-27
Filing date: 2019-11-27
Publication date: 2022-06-14
Anticipated expiration: 2039-11-27
Also published as: CN110773231A

Abstract

The invention discloses a preparation method of a nano-scale fuel oil catalytic oxidation-adsorption desulfurization catalyst. The heteropoly acid is used as an active component, the nanoscale layered hollow silica hollow sphere is used as a carrier, an amino group is grafted on the nanoscale layered hollow silica hollow sphere to obtain an amino-nanoscale layered hollow silica hollow sphere, and the heteropoly acid is dispersed on the surface of the amino-nanoscale layered hollow silica hollow sphere in a molecular form to obtain the heteropoly acid immobilized amino grafted layered hollow silica hollow sphere. The invention has simple preparation process, can efficiently reduce dibenzothiophene sulfides which are difficult to remove in fuel oil, greatly reduces the using amount of the catalyst, does not need an extraction process, has good circulation stability, realizes catalytic oxidation-adsorption desulfurization coupling in one step, improves the desulfurization efficiency of the catalyst, simplifies the desulfurization process flow, greatly reduces the industrial application cost, and has good application prospect in the aspect of catalytic oxidation desulfurization of the fuel oil.

Description

Preparation method of nano-scale fuel oil catalytic oxidation-adsorption desulfurization catalyst

Technical Field

The invention relates to a preparation method of a nano-scale catalytic oxidation adsorption desulfurization catalyst, in particular to a method for preparing a composite nano HPV-NH with high catalytic activity₂-a method for the desulfurization of HHSS catalysts.

Background

With the development of global industrialization, the problem of atmospheric pollution is increasingly severe. Harmful gas SO in atmospheric pollution₂The direct influence on the life, work and property safety of people is caused, for example, acid rain causes serious acid corrosion to trees, steel buildings, human skin, and the like, and serious pollution to water is caused. SO (SO)₂One of the main sources of the sulfur-containing gasoline is automobile exhaust emission, with the continuous increase of automobile holding capacity, according to related statistical results, the national automobile holding capacity can reach 2.5-2.9 hundred million vehicles in 2020, China already enters the automobile society, and in order to reduce negative environmental and health influences, the requirement of many countries and regions on the sulfur content in fuel oil is lower than 10ppm, so deep desulfurization and ultra-deep desulfurization become a global research subject, and 200In 0 year, the national gasoline standard executes the GB 17930-1999 standard nationwide, and the sulfur content is regulated to be below 800 ppm; in the end of 2009, the national gasoline standard executes the GB 17930-2006 standard nationwide, and the sulfur content is regulated to be 150 ppm; in 2009, the european union and the U.S. environmental protection agency respectively required maximum sulfur contents of 10ppm and 15ppm in gasoline; and beginning in 2017, the U.S. environmental protection agency requires that the maximum sulfur content in diesel oil is less than 10ppm, and national six standards are implemented in part of cities in China at present, and the sulfur content in gasoline is required to be 10 ppm. From the series of standards, it can be seen that the standard of sulfur content in gasoline in China is in international connection. Therefore, effective reduction of sulfur content in diesel oil has become a worldwide research hotspot, which will make the research work of ultra-deep desulfurization of petroleum products especially important.

At present, industrial desulfurization means mainly comprises a hydrodesulfurization technology and an oxidative desulfurization technology, wherein the hydrodesulfurization technology is hindered in the desulfurization industry due to harsh desulfurization conditions (300-350 ℃ and 5-10 MPa), high in cost and high in danger, and simultaneously has defects in deep desulfurization of fuel oil. Compared with hydrodesulfurization, oxidative desulfurization is favored by researchers at home and abroad due to high desulfurization rate, mild reaction conditions, environmental protection and the like. The core of Oxidation Desulfurization (ODS) is to oxidize the thiophene sulfides in the oil into sulfones or sulfoxides with stronger polarity, and the sulfones or sulfoxides with stronger polarity can be easily removed from the oil by adopting separation technologies such as extraction, adsorption, rectification and the like, thereby achieving the goal of desulfurization. The core of the oxidative desulfurization technology is the development of catalysts and oxidants in catalytic oxidative desulfurization systems, wherein H is₂O₂The heteropolyacid catalytic oxidation desulfurization system is widely concerned, mainly due to hydrogen peroxide (H)₂O₂) Cheap and easily available, wide sources, water as a product, and environmental protection; easy to separate from the oil product without changing the quality of the oil product. The oxidative desulfurization technology has the following disadvantages: the catalyst has large particles and long pore channels, so that the reaction time is long and the reaction speed is slow; the catalyst particles are too large, the adsorption and desorption speed is too slow, and the catalytic reaction and the product adsorption are not facilitated; the catalyst has low polarity and no adsorption performance, and can be used in DBTAfter being oxidized, polar organic solution such as ethanol or acetonitrile is needed for extraction, so that the desulfurization process is complex and the desulfurization cost is high; the consumption of hydrogen peroxide is large, so that the desulfurization cost is high; the catalytic oxidation step and the separation step of the sulfur-containing oxidation products are separated, the operation is complicated, and the efficiency is low.

Disclosure of Invention

The invention aims to provide a preparation method of a nano-scale fuel oil catalytic oxidation-adsorption desulfurization catalyst. The size of the catalyst prepared by the invention is about 100 nanometers, the catalyst has a structure that the small hollow spheres are gathered to form the large hollow spheres, amino groups are grafted by a silane coupling agent, and then the amino groups are immobilized with heteropoly acid through positive and negative charge acting force, so that the active components are dispersed to the maximum extent, the catalyst has very excellent catalytic performance, and the heteropoly acid and the amino groups are not easy to lose due to interaction, and the cycle stability is good. Meanwhile, the surface of the catalyst carrier is provided with a large number of polar groups (hydroxyl and amino), and sulfur-containing compounds (sulfones and sulfoxides) after high-polarity oxidation can be effectively adsorbed. The invention has simple preparation process, can efficiently reduce dibenzothiophene sulfides which are difficult to remove in fuel oil, greatly shortens the reaction time, and simultaneously reduces the dosage of the catalyst; the catalyst and the adsorbent have high adsorption capacity on sulfur-containing oxidation products, do not need an extraction desulfurization process, and have good circulation stability. The catalytic oxidation-adsorption desulfurization coupling is realized in one step, the desulfurization efficiency of the catalyst is improved, the desulfurization process flow is simplified, the industrial application cost is greatly reduced, and the method has a good application prospect in the aspect of catalytic oxidation desulfurization of fuel oil.

The technical scheme of the invention is as follows: a preparation method of a nanometer fuel oil catalytic oxidation-adsorption desulfurization catalyst comprises the steps of taking heteropoly acid as an active component, taking a nanometer level hollow silica hollow sphere as a carrier, grafting amino on the nanometer level hollow silica hollow sphere to obtain an amino-nanometer level hollow silica hollow sphere, dispersing heteropoly acid on the surface of the amino-nanometer level hollow silica hollow sphere in a molecular form, and preparing a heteropoly acid immobilized amino grafted level hollow silica hollow sphere.

In the preparation method of the nano-scale fuel catalytic oxidation-adsorption desulfurization catalyst, the heteropolyacid accounts for 10-50% of the total weight of the heteropolyacid immobilized amino grafted layered hollow silica hollow sphere.

In the preparation method of the nano-scale fuel oil catalytic oxidation-adsorption desulfurization catalyst, the heteropoly acid is H₃PW₁₂O₄₀、H₃PMo₁₂O₄₀、H₄SiW₁₂O₄₀、H₄PMo₁₁VO₄₀、H₅PMo₁₀V₂O₄₀、H₆PMo₉V₃O₄₀Any one of them.

The preparation method of the nano-scale fuel oil catalytic oxidation-adsorption desulfurization catalyst specifically comprises the following steps:

(1) adding the nano-scale layered hollow silica hollow spheres into absolute ethyl alcohol, performing ultrasonic dispersion, refluxing, suction filtration, washing and drying to obtain a product A;

(2) adding the product A into toluene, dropwise adding 3-aminopropyltriethoxysilane, refluxing, filtering, washing, and drying to obtain product B;

(3) and adding the product B into absolute ethyl alcohol, performing ultrasonic dispersion, adding heteropoly acid, uniformly stirring, refluxing, performing suction filtration, washing and drying to obtain the heteropoly acid immobilized amino grafted hierarchical hollow silica hollow sphere.

In the preparation method of the nano-scale fuel oil catalytic oxidation-adsorption desulfurization catalyst, in the step (1), 0.5-2g of nano-scale layered hollow silica hollow spheres which are not calcined and dried are proportionally added into 50-200mL of absolute ethyl alcohol.

In the preparation method of the nano-scale fuel oil catalytic oxidation-adsorption desulfurization catalyst, in the step (1), the ultrasonic dispersion time is 8-12min, the reflux is carried out for 4-8h under the protection of nitrogen, the reflux temperature is 75-85 ℃, and the nitrogen flow is 10-30 ml/min; washing with anhydrous ethanol for 2-4 times, and drying at 50-70 deg.C for 4-8 hr.

In the preparation method of the nano-scale fuel oil catalytic oxidation-adsorption desulfurization catalyst, in the step (2), 0.5-2g of the product A is added into 50-200ml of toluene according to the proportion, and then 0.25-1ml of 3-aminopropyltriethoxysilane is dropwise added.

In the preparation method of the nano-scale fuel oil catalytic oxidation-adsorption desulfurization catalyst, in the step (2), the reflux is carried out for 12-48h under the protection of nitrogen, the reflux temperature is 105-; washing with toluene for 2-4 times, and drying at 105-115 deg.C for 5-7 h.

In the preparation method of the nano-scale fuel oil catalytic oxidation-adsorption desulfurization catalyst, in the step (3), 0.5-2g of the B product is added into 50-200mL of absolute ethyl alcohol according to the proportion, and then the mixture is subjected to ultrasonic dispersion and 0.125-0.5g of heteropoly acid is added.

In the preparation method of the nano-scale fuel oil catalytic oxidation-adsorption desulfurization catalyst, in the step (3), ultrasonic dispersion is carried out for 2-4 min; refluxing for 4-8h under the protection of nitrogen, wherein the flow rate of the nitrogen is controlled at 20-30 ml/min; filtering, washing with anhydrous ethanol for 2-4 times, and drying at 105-115 deg.C for 10-14 h.

Note: the heteropolyacid is HPA, phosphotungstic acid (H)₃PW₁₂O₄₀) HPW, HHSS as the nano-scale layered hollow silica hollow sphere and NH as the amino-nano-scale layered hollow silica hollow sphere₂the-HHSS and heteropoly acid immobilized amino grafted hierarchical hollow silica hollow sphere is HPA-NH₂-HHSS。

Compared with the prior art, the invention has the following beneficial effects:

the invention uses dipping method to grow heteropoly acid small particles highly dispersed in molecular form on nano-level hollow spherical material HHSS to obtain composite HPA-NH₂The HHSS catalyst has the size of about 100 nanometers, has a structure that small hollow spheres are aggregated to form large hollow spheres, has a large specific surface area, and is rich in large polar groups on the surface. The catalyst prepared by the method has simple and efficient preparation conditions, the active components are highly dispersed on the surface of the carrier in molecules, the dispersibility is good, the catalyst activity is high, the stability is good, the desulfurization efficiency can reach 99.36% within 30min, and meanwhile, the surface of the catalyst carrier has a large number of polar groups (hydroxyl and amino) and can effectively adsorb the large polarityThe oxidized sulfur-containing compounds (sulfones and sulfoxides) are used as both catalysts and adsorbents, and the oxidized sulfur-containing compounds are not required to be extracted by a large polar solvent. Meanwhile, the carrier does not contain metal and has the advantages of low cost and the like, and can be widely applied to the production process of high-efficiency environment-friendly diesel oil.

Experiments prove that:

step one, the same as steps (1) and (3) of the preparation method of the embodiment of the invention, step (2) is omitted, and the carrier is HHSS without grafted amino groups, so that the HPW @ HHSS catalyst f is obtained. The following experiments were carried out on catalyst f and catalysts a, b, c, d, e prepared in examples 1 to 5 of the present invention:

0.431g of dibenzothiophene was placed in a 100ml beaker, 20ml of n-octane was added and dissolved with stirring, and the mixture was transferred to a dry 250ml volumetric flask and titrated to the scale line to obtain a simulated oil having a sulfur content of 300 ppm.

The catalyst f and the catalysts a, b, c, d and e prepared in examples 1 to 5 of the present invention were respectively carried out in a three-neck flask system simulating the catalytic performance of catalytic oxidation adsorption desulfurization of oil products and total reflux under the reaction conditions of 60 ℃ temperature, 0.06 amount of catalyst (sulfur content is 300ppm of simulated oil, oxidant is hydrogen peroxide, [ o ]/[ s ]: 2.5:1, and reaction time is 30 min). The dibenzothiophene conversion results obtained are shown in table 1:

TABLE 1 dibenzothiophene conversion

Catalyst and process for preparing same	Dibenzothiophene conversion (%)
		Example 1a	99.36
Example 2b	64.14
		Example 3c	97.56
Example 4d	95.67
		Example 5e	88.33
f	98.08

As can be seen by comparison, the loading of HPW is 20%, the most active sites are exposed, and the detachment efficiency is highest, and we have also tried to compound HPW and HHSS without grafted amino directly to obtain HPW @ HHSS, and the desulfurization rate is only 98.08%.

In the prior art: amino grafted MCM-41 molecule (HPW-NH) immobilized by phosphotungstic acid₂-MCM-41), catalyst particles larger than 1 micron, desulfurization time 180 minutes, oxygen to sulfur ratio 8:1, desulfurization efficiency 100% using methanol as extractant. The invention has the following patent technologies: HPA-NH₂in-HHSS, with HPW-NH₂HHSS was an example, with catalyst particles of 100nm, a desulfurization time of 30 minutes, an oxygen-sulfur ratio of 2.5:1, and a desulfurization efficiency of 99.36% without using any organic solvent.

The catalyst is in a nanometer level and has a special structure of a nanometer level hollow sphere, so that the catalytic speed of the catalyst is greatly improved and is shortened from 180 minutes to 30 minutes, the desulfurization efficiency reaches 99.36 percent, and the time of the whole desulfurization process is greatly shortened; meanwhile, the consumption of hydrogen peroxide is greatly reduced from 8:1 to 2.5:1, so that the cost of the desulfurization process is reduced; most importantly, the catalyst provided by the invention has a large polar group, so that the oxidized sulfur-containing compound can be directly adsorbed, other organic solvents are not required to be used as an extracting agent, an extraction process in a desulfurization process is omitted, and the desulfurization process cost and the operation cost are greatly reduced.

Secondly, the inventor aims at the HPW-NH with 20 percent of the HPW prepared in the example 1₂HHSS catalyst a the following experiments and analyses were carried out:

description of the drawings: OADS (catalytic oxidation-adsorption desulfurization)

1. FIG. 1 is a Scanning Electron Microscope (SEM) image of the carrier HHSS according to the present invention (a) and (b), (c) and (d) are the carrier HHSS and 20% HPW-NH, respectively₂-Transmission Electron Microscopy (TEM) images of HHSS catalyst;

FIG. 1 shows HHSS and 20% HPW-NH₂SEM and TEM images of HHSS catalyst. From the SEM image (FIG. 1a), we can see that HHSS with nanometer dimensions is composed of many hollow spheres with a diameter of about 20 nm. Most particles keep spherical symmetry, the outer surface is smooth, and the hierarchical hollow sphere structure of the small hollow sphere and the big hollow sphere can be clearly seen from the broken sphere. The TEM image (fig. 1c) also verifies the presence of the hierarchical hollow spheres HHSS with dimensions of 100nm on both sides. HHSS is formed by aggregation of small hollow spheres. FIGS. 1b and 1d show nano-sized HPW-NH, respectively₂SEM and TEM images of HHSS catalyst. From FIG. 1b it can be clearly seen that HHSS still retains the hierarchical hollow structure and morphology of the nanopores after the catalyst HPW is immobilized on the surface. By HPW-NH₂TEM image of HHSS catalyst (FIG. 1d) we can see large particles of HPW without agglomeration on the surface of HHSS, demonstrating that HPW is uniformly dispersed on the surface and inside of HHSS in the form of molecules.

2. FIG. 2 is a 20% HPW-NH of the invention₂-elemental profile of HHSS catalyst: (a) is a Scanning Transmission Electron Microscopy (STEM) image of 20% HPW-NH2-HHSS catalyst, (b) N, (c) O, (d) Si, (e) P and (f) W are 20% HPW-NH₂-elemental distribution (Mapping) diagram of HHSS catalyst;

20％HPW-NH₂scanning transmission electron microscopy (FIG. 2a) and elemental mapping (FIGS. 2b, c, d, e, f) of the-HHSS catalyst show the uniform distribution of the N, O, Si, P, W elements on the HHSS, indicating-NH₂Successful grafting on HHSS and successful immobilization of HPW on NH₂-HHSS.

3. FIG. 3 is a 20% HPW-NH of the invention₂-XPS diagram of HHSS catalyst; wherein (a) the total spectrum of the sample, (b) C1s, (C) N1s, (d) P2P, (e) W4f, (f) O1s and (g) Si 2P:

the XPS method was used to study the elemental composition and chemical state of a 20% HPW-NH2-HHSS catalyst. As shown in FIG. 3a, the sample consisted of C, O, N, Si, P, W. FIG. 3b shows the presence of element C1s (284.8eV) on HHSS, illustrating the grafting of APTES onto HHSS. In FIG. 3c, where the voltage is 400.08eV, a weak signal of N1s can also be seen, demonstrating that this was successful in grafting 3-aminopropyltriethoxysilane onto the HHSS surface. Also as shown in FIG. 3d, the weak peak of P2P at 133.22eV corresponds to P in HPW. FIG. 3e shows that the peaks at 35.46eV and 37.48eV belong to W4f, respectively_7/2And 4f_5/2Illustrate W⁶⁺-O-Si and W⁶⁺O-W in HPW-NH₂Chemical complexation on HHSS. The difference between the binding energies of Wf7/2 and Wf5/2 was 2ev, indicating that WO₃There is a surface of HHSS grafted with amino groups. As shown in FIG. 3f, oxygen is present in HPW and silica as can be seen from O1s binding energies of 526.9-538.25 eV. FIG. 3g shows peaks with values of 103.31eV and 154.33eV, corresponding to Si 2p, respectively, which are characteristic of Si in HHSS and Si element grafted into APTES on the surface of HHSS. These conclusions are related to HPW-NH₂Mapping and TEM images of HHSS remained consistent. Thus, it can be considered that HPW is successfully fixed to NH by a protonated amine bridge₂-HHSS.

4. FIG. 4 is a 20% HPW-NH of the invention₂HHSS catalyst, in which line a is the thermogram of HPW and line b is 20% HPW-NH₂Thermogram of HHSS, line C NH₂-a thermogram of HHSS, line d is a thermogram of HHSS;

pure HPW, 20% HPW-NH₂-HHSS,NH₂TGA analysis of the-HHSS and HHSS samples is shown in FIG. 4. The TGA profile of pure HPW (fig. 4a) shows that a weight loss step occurs around 186 ℃ with a rate of 4.8%, pertaining to the release of bound water molecules from HPW hydrates. No weight loss exists at 200-800 ℃, which indicates that the keggin type HPW is stable at high temperature. For the carrier HHSS (FIG. 4d), at 25 ℃ C. to EThe total weight loss rate is 44% in the 800 deg.c range, the first weight loss is between 25 deg.c and 200 deg.c, and the second weight loss is mainly caused by the dehydration of uncalcined hydroxyl radical in the surface of silica at 200 deg.c and 300 deg.c. As shown in FIG. 4c, NH₂The weight loss of the-HHSS sample in the range of 25-800 ℃ is the same as that of uncalcined HHSS (about 44%), but the thermal behavior is significantly different from that of pure HHSS. For example, NH₂the-HHSS nanocomposite shows a smaller hydroxyl dehydration peak at 200 ℃ and a larger weight loss peak at 400-500 ℃ due to decomposition of polar amino groups, and in addition, it can be seen that the weight loss peak shifts to a high temperature region due to incorporation of APTES into hollow pores. 20% HPW-NH at 25-800 deg.C₂The weight loss of-HHSS was 28.3%, due to the decomposition of the amino groups of HPW and HHSS (FIG. 4 b). 20% HPW-NH₂Decomposition ratio of HHSS to NH₂the-HHSS was 15.4% higher, indicating that HPW was well immobilized on amino-grafted HHSS. Results are compared with HPW-NH₂XPS analysis, Mapping and TEM images of HHSS remained consistent.

5. FIG. 5 is a 20% HPW-NH of the invention₂The catalytic oxidation-adsorption desulfurization performance of the HHSS catalyst is compared with that of different sulfur compounds, namely Benzothiophene (BT), Dibenzothiophene (DBT) and Dodecanethiol (DT);

FIG. 5 Studies 20% HPW-NH₂The effect of HHSS catalysts on the desulfurization of various sulfides by catalytic oxidation. The order of decreasing the activity of the oxidation reaction is DBT>DT>BT, has the lowest reactivity, which is associated with different electron densities on the sulfur atom. The electron density of the DBT sulfur atom is 5.758, the BT is 5.739, and the electron density of the DBT sulfur atom is higher than that of the BT, which indicates that the catalyst HPW-NH₂-HHSS has a higher catalytic oxidation activity on DBT than BT.

6. FIG. 6 is a 20% HPW-NH of the invention₂-HHSS catalyst, wherein A is 20% HPW-NH₂-comparison of catalytic oxidation-adsorption desulfurization performance of HHSS catalysts on simulated oils of different sulfur concentrations; b is 20% HPW-NH₂-maximum adsorption capacity curve of HHSS catalyst to sulfur (DBTO 2);

as shown in FIG. 6A, for the determination of nanoporous HPW-NH₂-the adsorption capacity of the HHSS catalyst,20% HPW-NH₂Samples of HHSS (60mg) were added to model fuel oils containing different concentrations of DBT. The results show that the removal rate of the method is higher, and the DBT is reduced along with the increase of the concentration. Furthermore, 300mg.L^-1Is the optimum concentration, and the desulfurization rate reaches the highest (99%) after 30min of reaction, mainly because of DBTO₂Is less than the maximum adsorption capacity. When the DBT concentration is greater than 400mg/L, the DBT removal rate decreases (FIG. 6A). The catalyst pair DBTO was calculated using the following expression₂Adsorption capacity of (2):

where qe is the adsorption capacity (mg.g) of the nanoporous catalyst^-1)，C_oAnd C_eInitial and equilibrium concentrations of S (mg.L), M is the mass of the catalyst, M is_DBOT2Is the molecular weight of dibenzothiophenesulfone, M_SMolecular weight V, which is sulfur, is the simulated oil mass (L). By calculation, 20% HPW-NH₂-HHSS catalyst couple DBTO₂Has an adsorption capacity of about 374mg.g^-1As shown in FIG. 6B

7. FIG. 7 is a 20% HPW-NH of the invention₂-HHSS catalyst, wherein (a) is the effect of temperature on desulfurization performance; (b) is the influence of Heteropolyacid (HPW) loading on desulfurization performance; (c) is the effect of oxygen-sulfur ratio on desulfurization performance; (d) the influence of the addition amount of the catalyst on the desulfurization performance;

to obtain the best removal of DBT in OADS systems, the reaction temperature, Heteropolyacid (HPW) loading, H were investigated₂O₂The influence of the reaction conditions such as the/DBT molar ratio (expressed as O/S) and the amount of catalyst added on the desulfurization rate. (OADS ═ catalytic oxidation-adsorption desulfurization)

The reaction temperature is also an important factor affecting the desulfurization process, as shown in FIG. 7 (a). The results show that the removal rate of DBT is directly related to temperature. The DBT removal was only 72.56% at 40 ℃ and reached a maximum (99.36%) at 60 ℃. This may be due to the large amount of W (O) generated by the temperature₂)_nThe active species forms a peroxide metal complex which,the oxidation capability of the catalyst to sulfide can be enhanced. Also, high temperatures increase desulfurization costs.

The HPW-NH is examined under the conditions of different HPW loading amounts (10-50 percent)₂DBT removal efficiency of the HHSS samples, constant weight of each catalyst (60mg), results are shown in FIG. 7 (b). The removal rates of the above samples at 60 ℃ for 30min were 65.32%, 99.36%, 95.29%, 93.44% and 88.23%, respectively. As can be seen, 20% HPW-NH₂The best catalytic performances of the-HHSS. The HPW content plays a key role in catalytic performance. 20% HPW-NH₂DBT removal of-HHSS higher than 10% HPW-NH₂-HHSS. The removal rate of DBT increases with continued loading of HPW until after its optimization point, the removal rate decreases. This phenomenon is associated with a gradual decrease in the BET surface area and pore volume of the sample. Therefore, DBT removal was 30%, 40% and 50% HPW-NH, respectively₂-HHSS lower than 20%. As can be seen from the above results, different amounts of HPW were uniformly and dispersedly fixed to the nano-sized NH₂-HHSS. In addition, the amino-functionalized system also has a variety of catalytically active sites and polar hydroxyl and amino groups, which act as adsorption centers in the OADS system.

In the OADS system, the amount of oxidant used is one of the major factors affecting the DBT removal rate. Using different [ O ]]/[S]Molar ratio a series of experiments were performed to verify the effect of the amount of oxidizing agent. As shown in FIG. 7(c), the effects of H2O2/DBT molar ratios of 0:1, 1:1, 2:1, 2.5:1, 3.5:1, and 4:1 on the removal rate were examined under the same conditions. In the OADS system, when H₂O₂In the absence, the DBT removal rate remained substantially unchanged (FIG. 7(c) [ O ]]/[S]0: 1). By reacting [ O]/[S]The content increased from 1:1 to 2.5:1, and in addition to this, the removal rate of DBT was greatly increased and decreased (fig. 7 (c)). The actual amount of H2O2 is greater than stoichiometric because the H2O2 oxidizing agent decomposes under heating. In addition, economic factors should be considered to minimize the use of hydrogen peroxide. Therefore, we believe that excess H is not required₂O₂And the best [ O ] is selected]/[S]＝2.5

In order to obtain the maximum OADS efficiency, a series of fresh foods with the dosage of 30-70mg are usedCatalyst 20% HPW-NH₂HHSS was used under the same conditions. As can be seen from FIG. 7(d), as the amount of catalyst used was increased from 30mg to 60mg, the DBT removal rate sharply increased from 35.5% to 92.45% in 10 minutes, and the DBT removal rate was increased from 59.23 to 99.36% after 30 minutes. When the dosage of the catalyst is increased from 60mg to 70mg, the DBT removal rate is slowly increased from 92.45% to 95.19% along with the gradual increase of the reaction time, and after the reaction time reaches 30min, the removal rates of the two catalysts reach 99.36%. As can be seen from FIG. 7(d), increasing the weight of the catalyst increases the desulfurization rate. This is due to the excess of catalytically active sites, which is related to the adsorption efficiency. However, when the catalyst mass was further increased to 70mg, the DBT removal rate did not change significantly, indicating that the adsorption capacity of the catalyst exceeded the amount of sulfur oxides. Therefore, the amount of the catalyst used in the OADS system is preferably 60 mg.

8. FIG. 8 is a 20% HPW-NH of the invention₂-desulfurization performance cycling stability test pattern of HHSS catalyst; in industrial applications, reusability and stability are two key factors affecting the performance of heterogeneous catalysts. 20% HPW-NH₂The HHSS S is recycled to the OADS system. As shown in FIG. 8, 20% HPW-NH₂The catalytic efficiency of HHSS is hardly reduced, from 99.36% to 99.24%. Demonstration of 20% HPW-NH₂the-HHSS catalyst has good reusability due to-NH₂There is a strong electronegativity between the positive charge of HPW, which prevents HPW from dissolving during washing with polar solvents.

HPA-NH prepared by the Applicant's working-up of other examples₂HHSS was tested and analyzed according to the experiments described in 1 to 8 above, and the results obtained were comparable to those of the above tests and analyses.

In conclusion, the invention has the advantages of simple preparation process, capability of efficiently reducing dibenzothiophene sulfides which are difficult to remove in fuel oil, greatly shortened reaction time and reduced catalyst consumption; the catalyst and the adsorbent have high adsorption capacity on sulfur-containing oxidation products, do not need an extraction desulfurization process, and have good circulation stability. The catalytic oxidation-adsorption desulfurization coupling is realized in one step, the desulfurization efficiency of the catalyst is improved, the desulfurization process flow is simplified, the industrial application cost is greatly reduced, and the method has the beneficial effects of good application prospect in the aspect of catalytic oxidation desulfurization of fuel oil.

Drawings

FIG. 1 is SEM and TEM images of the carrier HHSS according to the invention (a) and (c), respectively, (b) and (d) are 20% HPW-NH₂-SEM and TEM images of HHSS catalyst;

FIG. 2 shows that (a) according to the invention is 20% HPW-NH₂TEM image of the HHSS catalyst, N (b), O (c), Si (d), P (e) and W (f) are 20% HPW-NH₂-Mapping profile of HHSS catalyst;

FIG. 3 is 20% HPW-NH of the invention₂-XPS diagram of HHSS catalyst; wherein (a) the total spectrum of the sample, (b) C1s, (C) N1s, (d) P2P, (e) W4f, (f) O1s and (g) Si 2P;

FIG. 4 is a 20% HPW-NH of the invention₂HHSS catalyst, in which line a is the thermogram of HPW and line b is 20% HPW-NH₂-a thermogram of HHSS, line c a thermogram of NH2-HHSS, line d a thermogram of HHSS;

FIG. 5 is a comparison of catalytic oxidation-adsorption desulfurization performance of the 20% HPW-NH2-HHSS catalyst of the present invention for different sulfur compounds Benzothiophene (BT), Dibenzothiophene (DBT), Dodecanethiol (DT);

FIG. 6 is a 20% HPW-NH according to the invention₂-graph of catalytic performance and adsorption capacity of HHSS catalyst, where A is 20% HPW-NH₂-comparison of catalytic oxidation-adsorption desulfurization performance of HHSS catalysts on simulated oils of different sulfur concentrations; b is 20% HPW-NH₂-HHSS catalyst vs. Sulfur (DBTO)₂) Maximum adsorption capacity curve of (a);

FIG. 7 is a 20% HPW-NH according to the invention₂-HHSS catalyst, wherein (a) is the effect of temperature on desulfurization performance; (b) is the influence of Heteropolyacid (HPW) loading on desulfurization performance; (c) is the oxygen to sulfur ratio [ O ]]/[S](molar ratio) influence on desulfurization performance; (d) the influence of the addition amount of the catalyst on the desulfurization performance;

FIG. 8 is a 20% HPW-NH according to the invention₂-desulfurization performance cycling stability test chart of HHSS catalyst.

Detailed Description

The invention is further illustrated by the following figures and examples, which are not to be construed as limiting the invention.

A preparation method of a nano-scale fuel oil catalytic oxidation-adsorption desulfurization catalyst specifically comprises the following steps:

(1) according to the proportion, 0.5-4g of HHSS which is not calcined and dried is added into 50-200mL of absolute ethyl alcohol, the ultrasonic dispersion time is 8-30min, the reflux is carried out for 2-8h under the protection of nitrogen, the reflux temperature is 75-85 ℃, and the nitrogen flow is 10-30 mL/min; washing with anhydrous ethanol for 2-4 times, and drying at 50-100 deg.C for 4-12 hr to obtain product A;

(2) proportionally adding 0.5-4g of the A product into 50-200ml of toluene, dropwise adding 0.1-4ml of APTS, refluxing for 12-48h under the protection of nitrogen, wherein the refluxing temperature is 105-115 ℃, and the nitrogen flow is 10-30 ml/min; washing with toluene for 2-4 times, and drying at 105-115 deg.C for 5-7h to obtain product B (NH)₂-HHSS)；

(3) Proportionally mixing 0.5-4g of product B (NH)₂HHSS) is added into 50-200mL of absolute ethyl alcohol, ultrasonic dispersion is carried out for 2-4min, 0.125-2g of HPW is added, stirring is carried out evenly, reflux is carried out for 2-8h under the protection of nitrogen, and the flow rate of the nitrogen is controlled to be 10-30 mL/min; filtering, washing with anhydrous ethanol for 2-4 times, and drying at 80-120 deg.C for 4-24 hr to obtain HPW-NH₂-a HHSS catalyst.

The step (1) is preferably: according to the proportion, 0.5-2g of HHSS which is not calcined and dried is added into 50-200mL of absolute ethyl alcohol, the ultrasonic dispersion time is 8-12min, the reflux is carried out for 4-8h under the protection of nitrogen, the reflux temperature is 75-85 ℃, and the nitrogen flow is 10-30 mL/min; washing with anhydrous ethanol for 2-4 times, and drying at 50-70 deg.C for 4-8 hr to obtain product A;

the step (2) is preferably: adding 0.5-2g of A into 50-200ml of toluene, then dropwise adding 0.25-1ml of APTS, refluxing for 12-48h under the protection of nitrogen, wherein the refluxing temperature is 105-115 ℃, and the nitrogen flow is 10-30 ml/min; washing with toluene for 2-4 times, and drying at 105-115 deg.C for 5-7h to obtain product B (NH)₂-HHSS)；

The step (3) is preferably: proportionally mixing 0.5-2g of product B (N)H₂-HHSS) is added into 50-200mL of absolute ethyl alcohol, ultrasonic dispersion is carried out for 2-4min, 0.125-0.5g of HPW is added, stirring is carried out evenly, reflux is carried out for 4-8h under the protection of nitrogen, and the flow rate of the nitrogen is controlled to be 20-30 mL/min; filtering, washing with anhydrous ethanol for 2-4 times, and drying at 105-115 deg.C for 10-14h to obtain HPW-NH₂-a HHSS catalyst.

Examples 1-5 were prepared according to the procedure described above to give HPW as HPW-NH₂-HPW-NH in an amount of 10 to 50% of the total weight of HHSS₂-HHSS, wherein: example 1 obtaining HPW of 20% HPW-NH₂-HHSS catalyst a; example 2 obtaining HPW 10% HPW-NH₂-HHSS catalyst b; example 3 obtaining a HPW of 30% HPW-NH₂HHSS catalyst c, HPW-NH 40% HPW obtained in example 4₂HHSS catalyst d, HPW-NH with 50% HPW obtained in example 5₂HHSS catalyst e, in particular as follows:

catalyst preparation example 1: 20% HPW-NH₂Preparation of HHSS

The step (1) and the step (2) are carried out as described above, and the step (3) is carried out by mixing 0.5-2g of the B product (NH)₂HHSS) is added into 50 to 200mL of absolute ethyl alcohol, ultrasonic dispersion is carried out for 2 to 4min, 0.125 to 0.5g of HPW is added, stirring is carried out evenly, reflux is carried out for 4h under the protection of nitrogen, and the flow rate of the nitrogen is controlled at 20 mL/min; filtering, washing with anhydrous ethanol for 2 times, and drying at 105 deg.C for 10 hr to obtain 20% HPW-NH₂-a HHSS catalyst.

Catalyst preparation example 2: 10% HPW-NH₂Preparation of HHSS

Step (1) and step (2) are carried out as described above, and step (3) is carried out by mixing 0.5-2g of product B (NH)₂HHSS) is added into 50 to 200mL of absolute ethyl alcohol, ultrasonic dispersion is carried out for 2 to 4min, 0.075 to 0.25g of HPW is added, stirring is carried out evenly, reflux is carried out for 6h under the protection of nitrogen, and the flow rate of the nitrogen is controlled at 25 mL/min; filtering, washing with anhydrous ethanol for 3 times, and drying at 110 deg.C for 12 hr to obtain 10% HPW-NH₂-a HHSS catalyst.

Catalyst preparation example 3: 30% HPW-NH₂Preparation of HHSS

The step (1) and the step (2) are carried out as described above, and the step (3) is carried out by mixing 0.5-2g of the B product (NH)₂HHSS) is added into 50 to 200mL of absolute ethyl alcohol, ultrasonic dispersion is carried out for 2 to 4min, 0.2 to 0.75g of HPW is added, stirring is carried out evenly, reflux is carried out for 6h under the protection of nitrogen, and the flow rate of the nitrogen is controlled at 25 mL/min; filtering, washing with anhydrous ethanol for 3 times, and drying at 110 deg.C for 12 hr to obtain 30% HPW-NH₂-a HHSS catalyst.

Catalyst preparation example 4: 40% HPW-NH₂Preparation of HHSS

The step (1) and the step (2) are carried out as described above, and the step (3) is carried out by mixing 0.5-2g of the B product (NH)₂HHSS) is added into 50 to 200mL of absolute ethyl alcohol, ultrasonic dispersion is carried out for 2 to 4min, 0.325 to 1.33g of HPW is added, stirring is carried out evenly, reflux is carried out for 6h under the protection of nitrogen, and the flow rate of the nitrogen is controlled at 25 mL/min; filtering, washing with anhydrous ethanol for 3 times, and drying at 110 deg.C for 12 hr to obtain 40% HPW-NH₂-a HHSS catalyst.

Catalyst preparation example 5: 50% HPW-NH₂Preparation of HHSS (e)

The step (1) and the step (2) are carried out as described above, and the step (3) is carried out by mixing 0.5-2g of the B product (NH)₂HHSS) is added into 50-200mL of absolute ethyl alcohol, ultrasonic dispersion is carried out for 2-4min, 0.5-2g of HPW is added, stirring is carried out evenly, reflux is carried out for 8h under the protection of nitrogen, and the flow rate of the nitrogen is controlled at 30 mL/min; filtering, washing with anhydrous ethanol for 4 times, and drying at 115 deg.C for 14 hr to obtain 50% HPW-NH₂-a HHSS catalyst.

Catalyst preparation example 6: preparation of 20% HPW-HHSS (f)

Step (1) is carried out as described above, step (2) is omitted, step (3) is carried out according to the proportion, 0.5-2g of A product (HHSS) is added into 50-200mL of absolute ethyl alcohol, ultrasonic dispersion is carried out for 2-4min, 0.125-0.5g of HPW is added, stirring is carried out uniformly, reflux is carried out for 6h under the protection of nitrogen, and the flow rate of the nitrogen is controlled at 25 mL/min; and (3) carrying out suction filtration, washing for 3 times by adopting absolute ethyl alcohol, and drying for 12 hours at the temperature of 110 ℃ to obtain the 20 percent HPW-HHSS catalyst.

Catalyst preparation example 7: synthesis of other nano-scale heteropolyacid catalysts

By varying the heteropolyacid (H) used₃PW₁₂O₄₀(HPW)、H₃PMo₁₂O₄₀(HPM)、H₄SiW₁₂O₄₀(HSW)、H₄PMo₁₁VO₄₀(HPMV)、H₅PMo₁₀V₂O₄₀(HPMV2) and H₆PMo₉V₃O₄₀(HPMV3)), synthesized NH₂the-HHSS supported heteropoly acid catalyst comprises the following 6 catalysts: HPW-NH₂-HHSS、HPM-NH₂-HHSS、HSW-NH₂-HHSS、HPMV-NH₂-HHSS、HPMV2-NH₂HHSS and HPMV3-NH₂-HHSS。

The inventors also aimed at 20% HPW-NH₂-HHSS catalyst the following experiments were carried out:

and (3) desulfurization application: a model oil with a sulfur content of 300ppm was prepared by dissolving Dibenzothiophene (DBT) in n-octane. OADS of model fuels were performed in a three-necked flask equipped with a total reflux apparatus. Unless otherwise specified, the catalytic oxidation adsorption reaction is carried out at a temperature of 40-70 ℃, 10ml of model oil and 30-70mg of catalyst are added, and a certain amount of 30% H₂O₂Aqueous solutions (oxygen to sulfur ratio 1:1 to 4.5: 1). The reaction apparatus was set in a water bath at different temperatures and stirred and refluxed. Samples were collected at intervals, the supernatant was centrifuged and the sulfur content of the samples was analyzed using a microcoulomb sulfur meter (WK-2D). And after the reaction is finished, centrifugally recovering the solid catalyst for recycling. The conversion (. eta.) of DBT can be calculated according to the following equation_OAnd C represents the initial and final concentration of sulfur, respectively).

η＝[(C_O-C)/C_O]×100％

Desulfurization experiment example 1: 20% HPW-NH₂-HHSS catalyst for Dibenzothiophene (DBT) -n-octane system:

a model oil with a sulfur content of 300ppm was prepared by dissolving Dibenzothiophene (DBT) in n-octane. The OADS of model fuel was carried out in a three-necked flask equipped with a total reflux unit, the reaction was carried out at 60 deg.C, 10ml of model oil and 60mg of catalyst, a fixed amount of 30% H₂O₂Aqueous solution (oxygen to sulfur ratio 2.5: 1). The reaction apparatus was set in a water bath at different temperatures and stirred and refluxed. Every 5 minutesAnd (3) collecting a sample once, centrifuging and taking supernatant, and measuring that the desulfurization efficiency reaches 99.36 percent in 30 minutes. And after the reaction is finished, centrifugally recovering the solid catalyst for recycling.

Desulfurization experiment example 2: 20% HPW-NH₂-HHSS catalyst for Benzothiophene (BT) -n-octane system:

a model oil having a sulfur content of 300ppm was prepared by dissolving Benzothiophene (BT) in n-octane. The OADS of model fuel was carried out in a three-necked flask equipped with a total reflux unit, the reaction was carried out at 60 deg.C, 10ml of model oil and 60mg of catalyst, a fixed amount of 30% H₂O₂Aqueous solution (oxygen to sulfur ratio 2.5: 1). The reaction apparatus was set in a water bath at different temperatures and stirred and refluxed. Samples were collected every 5 minutes, and the supernatant was centrifuged to determine a desulfurization efficiency of 65.23% in 30 minutes. And after the reaction is finished, centrifugally recovering the solid catalyst for recycling.

Desulfurization experiment example 3: 20% HPW-NH₂-HHSS catalyst for Dodecanethiol (DT) -n-octane system:

a model oil having a sulfur content of 300ppm was prepared by dissolving Dodecanethiol (DT) in n-octane. The OADS of model fuel was carried out in a three-necked flask equipped with a total reflux unit, the reaction was carried out at 60 deg.C, 10ml of model oil and 60mg of catalyst, a fixed amount of 30% H₂O₂Aqueous solution (oxygen to sulfur ratio 2.5: 1). The reaction apparatus was set in a water bath at different temperatures and stirred and refluxed. Samples were collected every 5 minutes, and after centrifugation, the supernatant was collected, and the desulfurization efficiency reached 80.72% in 30 minutes. And after the reaction is finished, centrifugally recovering the solid catalyst for recycling.

The study found that 20% HPW-NH₂The HHSS catalyst can perform catalytic oxidation-adsorption on various sulfur-containing compounds (such as DBT, DT and BT), and the desulfurization efficiency is in the order of DBT>DT>BT, where the catalyst was found to have the lowest efficiency for BT removal, catalyst HPW-NH₂The best catalytic oxidation activity and adsorption capacity of the-HHSS on DBT are achieved.

Claims

1. A preparation method of a nano-scale fuel oil catalytic oxidation-adsorption desulfurization catalyst is characterized by comprising the following steps: taking heteropoly acid as an active component, taking the nano-scale layered silicon dioxide hollow sphere as a carrier, grafting amino on the nano-scale layered silicon dioxide hollow sphere to obtain an amino-nano-scale layered silicon dioxide hollow sphere, dispersing the heteropoly acid on the surface of the amino-nano-scale layered silicon dioxide hollow sphere in a molecular form, and preparing a heteropoly acid immobilized amino grafted layered silicon dioxide hollow sphere;

the amino-nanoscale layered silicon dioxide hollow spheres are large hollow spheres formed by gathering small hollow spheres;

the heteropolyacid accounts for 10-50% of the total weight of the heteropolyacid immobilized amino grafted hierarchical silicon dioxide hollow sphere;

the heteropoly acid is H₃PW₁₂O₄₀、H₃PMo₁₂O₄₀、H₄SiW₁₂O₄₀、H₄PMo₁₁VO₄₀、H₅PMo₁₀V₂O₄₀、H₆PMo₉V₃O₄₀Any one of them.

2. The preparation method of the nano-scale fuel oil catalytic oxidation-adsorption desulfurization catalyst according to claim 1, characterized in that: the method specifically comprises the following steps:

(1) adding the nano-scale layered silica hollow spheres into absolute ethyl alcohol, performing ultrasonic dispersion, refluxing, suction filtration, washing and drying to obtain a product A;

(3) and adding the product B into absolute ethyl alcohol, performing ultrasonic dispersion, adding heteropoly acid, uniformly stirring, refluxing, performing suction filtration, washing and drying to obtain the heteropoly acid immobilized amino grafted hierarchical silicon dioxide hollow sphere.

3. The preparation method of the nano-scale fuel oil catalytic oxidation-adsorption desulfurization catalyst according to claim 2, characterized in that: in the step (1), 0.5-2g of nano-scale layered silica hollow spheres which are not calcined and dried are proportionally added into 50-200mL of absolute ethyl alcohol.

4. The preparation method of the nano-scale fuel oil catalytic oxidation-adsorption desulfurization catalyst according to claim 2, characterized in that: in the step (1), the ultrasonic dispersion time is 8-12min, the reflux is carried out for 4-8h under the protection of nitrogen, the reflux temperature is 75-85 ℃, and the nitrogen flow is 10-30 mL/min; washing with anhydrous ethanol for 2-4 times, and drying at 50-70 deg.C for 4-8 hr.

5. The preparation method of the nano-scale fuel oil catalytic oxidation-adsorption desulfurization catalyst according to claim 2, characterized in that: in the step (2), 0.5-2g of the product A is added into 50-200mL of toluene according to the proportion, and then 0.25-1mL of 3-aminopropyltriethoxysilane is dripped.

6. The preparation method of the nano-scale fuel oil catalytic oxidation-adsorption desulfurization catalyst according to claim 2, characterized in that: in the step (2), refluxing is carried out for 12-48h under the protection of nitrogen, wherein the refluxing temperature is 105 ℃ and 115 ℃, and the nitrogen flow is 10-30 mL/min; washing with toluene for 2-4 times, and drying at 105-115 deg.C for 5-7 h.

7. The preparation method of the nano-scale fuel oil catalytic oxidation-adsorption desulfurization catalyst according to claim 2, characterized in that: in the step (3), 0.5-2g of the B product is added into 50-200mL of absolute ethyl alcohol according to the proportion, ultrasonic dispersion is carried out, and 0.125-0.5g of heteropoly acid is added.

8. The preparation method of the nano-scale fuel oil catalytic oxidation-adsorption desulfurization catalyst according to claim 2, characterized in that: in the step (3), ultrasonic dispersion is carried out for 2-4 min; refluxing for 4-8h under the protection of nitrogen, wherein the flow rate of the nitrogen is controlled at 20-30 mL/min; filtering, washing with anhydrous ethanol for 2-4 times, and drying at 105-115 deg.C for 10-14 h.